This invention relates generally to safety devices for hollow bore medical needles and particularly to medical syringe, butterfly and other hollow bore needle products and especially pre-filled syringes which employ protective needle sheaths for securely shielding sharp medical needle tips after being withdrawn from a patient and, still more particularly, to safety devices which can be affixed to a needle product at the end of a manufacturing cycle. This invention also particularly relates to sheaths or shrouds which are extended to a locked, needle-covering position after the needle is withdrawn from the patient.
Problems associated with inadvertent needle sticks are well known in the art of blood sampling, percutaneous medication injection and other medical procedures involving uses of medical needles. Ever increasing attention is being paid to needle stick problems due to the contemporary sensitivity of exposure to AIDS, Hepatitis and other serious blood-borne diseases.
Commonly, procedures involving removing a needle from a patient require a technician to use one hand to place pressure at the wound site where the needle is being withdrawn while removing the needle apparatus with the other hand. It is common practice for a tending technician to give higher priority to care for the wound than is given to disposal of a needle. In the case of commonly used, non-safety devices such priority either requires convenience of an available sharps container within ready reach or another means for safe disposal without leaving the patient""s side. Providing adequate care is often compounded by patient condition and mental state (e.g. in burn units and psychiatric wards). Under such conditions, it is often difficult, if not impossible, to use appropriate procedures to properly dispose of a used, exposed needle while caring for a patient.
Widespread knowledge and history associated with needle care and disposal problems have resulted in conception and disclosure of a large number of devices each of which represents an attempt to provide not only a solution to the problem of needle sticks, but also a device which is commercially viable (i.e. cost and price competitive with currently used non-safety devices).
Examples of disclosures of safety devices which protect needles by moving a protective shield over a sharp end of a syringe or other hollow bore medical needle are found in U.S. Pat. No. 5,348,544, issued Sep. 20, 1994 to Sweeney et al. (Sweeney), U.S. Pat. No. 5,246,428 issued Sep. 21, 1993 to Donald W. Falknor (Falknor), U.S. Pat. No. 5,256,153 issued Oct. 26, 1993 to Lawrence W. Hake (Hake), U.S. Pat. Nos. 5,139,489 and 5,154,285, issued Aug. 18, 1992 and Oct. 13, 1992, respectively, to William H. Hollister (Hollister) and U.S. Pat. No. 5,823,997 issued Oct. 20, 1998 and U.S. Pat. No. 5,980,488 issued Nov. 9, 1999 to David L. Thorne (Thorne). There are many other examples of safety devices which retract needles into housings, however, this instant invention is more directly related to devices which extend a shield over a needle rather than to those which employ needle retraction.
Sweeney discloses a device comprising a guard which is manually, slidably movable along a needle canula from a position proximal to a user to a distal position where the needle tip is shielded. The device comprises a hinged arm which extends along the needle canula and which is moved distally to collapse upon itself to extend the guard over the tip. Access to the tip is taught to be denied by a metallic clip associated with the guard, although, if the guard is securely affixed along the needle, the Sweeney device may be provided without a metallic clip. An alternative embodiment is also disclosed by which the manual operation is augmented by a spring. A device based upon Sweeney is currently being distributed by Becton Dickinson and Company, Franklin Lakes, N.J. in which three separate parts (two injection molded and one metal clip) are used to mechanize the guard. Once the device is extended to shield a needle tip, it cannot be easily reset to recover use of the needle for a subsequent procedure. Also, the hinged arm requires activation in the region of the needle itself and comprises parts which are of a size which occasionally impedes a user""s line of sight to insertion locations.
Falkner, and related disclosures, disclose devices comprising shields which are automatically releasible to extend distally from a user to cover a needle. The devices comprise latch mechanisms which are manually switched between unlatched and latched positions to free the needle for use and lock the shield over the needle, respectively. Of course, position of the latch mechanism provides a visual interpretation of the safety of the device (i.e. whether or not a latch is engaged), but that is the only safety mechanism and a xe2x80x9cmissedxe2x80x9d indicator of latch mechanism position may be possible in stressful circumstances. When the latch mechanism is in the unlatched position, access to the needle is not only possible, but likely when the front of the device is impacted by a body part. In addition, the shield, though made of transparent material, covers a portion of an attached syringe body until fully extended and may make portions of volume measurement indicia on the syringe body difficult to read with accuracy when the syringe is being used in a titrating application.
Hake is representative of disclosure of devices comprising a manually slidable guard which is disposed over a syringe body during a medical procedure involving a medical syringe needle and manually, slidably moved distally into a needle guarding position usually at the end of the procedure. Commonly users of such devices complain of difficulty of seeing measurement indicia while the guard is disposed over the syringe body and of danger of inadvertent needle sticks while sliding the guard distally to cover the needle. As well, it is generally difficult to determine whether a guard is in a locked or unlocked state when it covers the needle, making an additional possibility of inadvertent needle stick.
Hollister discloses a needle protection device which may be used with a double-ended needle assembly or with a simpler single needle system. The protection device comprises a substantially rigid housing flexibly connected to a container (for a vacuum tube sampling system) or to a needle hub. To exercise the protection device, the rigid member is pivotally rotated into engagement with an exposed needle of the double-ended needle assembly and is securely affixed to the exposed needle. A major drawback of the needle protection device of Hollister is the size and position of the rigid housing. During use of a needle assembly or system in a medical procedure, length and position of the housing member is considered by some to be inconvenient. A second drawback is the requirement either for two handed operation to pivot the housing to engage the needle or for the requirement to find and use a stable support surface against which the housing is pressed while the needle is swung into engagement with the housing. In a currently marketed format, an integral container holder version of the device disclosed by Hollister comprises two injection molded parts which permit the housing to be rotated, as much as possible, out of the way during a medical procedure. Such a format requires five injection molded parts, including a disposable needle assembly.
Thorne discloses a needle sheath which folds about a medical needle to permit access to the needle in a medical procedure. The sheath is hingeably attached to a structure (e.g. a needle hub or phlebotomy barrel) at a point away from a sharpened needle tip which is later enclosed by the needle sheath to protect a user from a stick by the needle tip. At the end of the procedure, the sheath is unfolded and extended away from the structure in the direction of the needle tip to encase and thereby protect users from contact with the needle and its tip. To permit the sheath to unfold about the needle, each folded part of the sheath is serially constructed of a plurality of rigid segments. At least one segment comprises an orifice through which the needle passes and about which that segment rotates while the sheath is being extended. Each segment is connected to at least one other segment by a hinge, which is preferably a molded, living hinge, and comprises a channel into which the needle nests when the sheath is fully extended. At least one of the segments comprises a catch which securely captures the needle when it is disposed in the sheath. Once the sheath is extended and the needle so captured, the combination of sheath and needle form a substantially rigid member which shrouds the needle and its sharpened tip to provide safety from dangerous contact with the tip and needle.
While folded needle sheaths, such as those disclosed in Sweeney and Thorne have desirable features related to needle safety and simplicity of actuation, all known foldable needle sheaths have severe disadvantages when attempts are made to affix such sheaths to needle devices already assembled. Generally, needle covers affixed over related medical needles are made to conform to pre-existing needle hub geometry. The known foldable needle sheaths depend upon a structure which is disposed about the needle in one way or another, resulting in a design change to accommodate one of the known safety shields.
This is a serious concern when considering the vast investment commonly made in automated assembly equipment and the additional cost of remodeling such equipment to install a safety sheath assembly in the middle of an existing automated line. In some cases, devices as taught by Thorne have been configured to fit over a needle cover and thereby affixed at the end of an automated line, but a natural consequence of a device which employs a foldable sheath having parts which must be disposed about a needle is a sheath or shield which significantly increases the girth of the device in the area of the device needle hub (e.g. in the case of a syringe, in the area of the distal end of the syringe barrel).
Generally, other than acceptance of the type of operation offered by such devices, commercial viability is dependent upon manufacturing cost. Purchase decisions in the area in which these devices are used are very cost sensitive. If gains in either improvement in safety or in labor savings are not found to make a device sufficiently competitive with contemporary competitive items, those devices are usually not found to be commercially viable. This same cost sensitivity applies to cost of refurbishing an automated assembly line to accommodate a safety needle shield.
In brief summary, the novel invention disclosed herein dramatically diminishes known major problems resulting from injury-related needle sticks which occur when needle tips are bared as medical needles are withdrawn from a patient at the end of a needle insertion procedure, but, perhaps more important to general patient welfare, these inventions provide opportunity for fabrication of a very low cost safety needle system. This opportunity is augmented by a further opportunity to affix a safety sheath assembly to a standard, completely assembled needle device at the end of an automated assembly line, requiring little or no changes to the device itself or to the automated assembly line, associated with manufacture and assembly of the device.
For purposes of this disclosure, a needle xe2x80x9cshieldxe2x80x9d is defined to be apparatus which protectively covers a medical needle for safety. A xe2x80x9csheathxe2x80x9d is a portion of a shield apparatus which encases or encloses the medical needle to serve as the critical element of the shield. An interlock is a combination of parts of a needle shield which act to urge displaced portions or members of a needle sheath into planar alignment relative to an associated medical needle and to achieve substantial rigidity of the portions or members thereby. As an example, an interlock may be associated with a first sheathing portion or member which is rotated and contacts a second sheathing portion to thereby cause the second sheathing portion or member to become rigidly affixed relative to the medical needle and first sheathing portion or member when the needle shield is unfolded and the shield is latched in a safety orientation relative to the medical needle. Also, for purposes of this disclosure, the term xe2x80x9cspurxe2x80x9d is defined to be an appendage distending from a one sheathing part to contact and urge a contacted portion of a second sheathing part in a direction of travel of the spur. Such a spur is thereby considered to be a part of an interlock.
It is a primary object to provide an unfoldable medical needle shield apparatus associated with a medical needle device which is folded into a compact state to permit access to a medical needle and an associated distally disposed sharpened tip for use in a medical procedure and unfolded and displaced about the medical needle to provide a protective safety sheath about at least the distally disposed sharpened tip of the medical needle, the shield apparatus comprising:
a shield connector assembly whereby the needle shield apparatus is securely affixed to the medical needle device;
a needle shield, hingeably affixed to the shield connector assembly, which provides the foldable portion of the apparatus, the shield comprising:
a proximally disposed substantially rigid, elongated first sheath member comprising a first end at which the shield is hingeably affixed to the connector assembly such that the proximal sheath member rotates in-line with the medical needle when the shield is unfolded and extended and a second end which is distally disposed relative to the first end when the shield is unfolded;
a substantially rigid, elongated second sheath member comprising a connected end hingeably affixed to the second end such that the second sheath member also rotates in-line with the medical needle when the shield is unfolded and an end free of connection to any other part when the shield is folded, the first sheathing member, in combination with the second sheathing member, comprising a length which extends along the length of the medical needle for safety when the shield is unfolded and at least the second sheath member being disposed about and sheathing the needle;
at least one latch associated with the shield by which the shield is unreleasibly latched to be securely affixed in place relative to the medical needle and associated sharpened tip when the shield is unfolded and disposed about the needle; and
the second end, in combination with the connected end, further comprising an interlock by which the second sheath member is forced into alignment with the needle as the shield is unfolded and securely latched as a safety sheath about the medical needle.
It is a further object to provide a spur which acts to engage the interlock.
It is an object to provide a button on the first sheathing member which facilitates unfolding of the shield.
It is an object to provide a latch and catch associated with the shield connector assembly and elongated first sheath member, in combination, which securely retains the shield apparatus about the medical needle when the shield apparatus is unfolded and so disposed.
It is an object to provide structure associated with the medical needle shield apparatus which permits the medical needle shield apparatus to be affixed to the medical needle device without impacting operational removal of a cover disposed about the medical needle and associated tip during storage and transport of the medical needle device before use.
It is an object to provide a second sheath member having a groove in the connection free end which acts as a track within which the medical needle glides as the needle shield is unfolded.
It is an object to provide a combination of sheath members whereby the second sheath member is longer than the first sheathing member to effectively impede binding as the needle shield unfolds.
It is an important object to provide a method for enclosing a sharpened medical needle in a safety shield comprising the steps of:
providing a medical needle device comprising a hollow bore cannula securely affixed in a hub and aseptically covered by a needle cover, the cannula having at least one sharpened tip to form the medical needle, and a safety shield assembly which is hingeably joined to the hub after assembly of the medical needle device, the safety shield assembly comprising an elongated, foldable sheath which comprises a pair of serially interconnected substantially rigid segments each of which being interconnected to the adjacent segment by an intersegment hinge, a first segment comprising a free end, which is unattached to any other portion of the part, and a second segment, in combination with the first segment, providing an interlock which acts about the intersegment hinge to force the segment with the free end against the needle as the sheath is unfolded, and comprising a channel in which at least a part of the cannula is disposed when the sheath is linearly extended, the sheath and the hinges being disposed to permit folding of the sheath about the hub in a first state to permit usable access to the medical needle in a medical procedure and unfolding and extending of the sheath to a substantially planar disposition along the cannula whereat the cannula is disposed along the channel, the sheath further comprising at least one latching member which catches and securely affixes the sheath in relation to the cannula, the sheath and cannula, in combination, thereby forming a substantially rigid body which protectively encloses the sharpened tip and denies access thereto;
assembling the medical needle device without the safety shield assembly;
affixing the safety shield assembly to the medical needle device to form a safety medical needle device;
transporting and storing the safety medical needle device prior to use;
removing the safety medical needle device from storage preparatory for use;
removing the needle cover from the cannula and folded sheath, leaving the shield assembly in a compact, stable, but releasible, state such that the needle tip is accessible for a medical procedure; and
at the end of the medical procedure, displacing a proximal segment of the sheath to unfold segments of the sheath, forcing the interlock to engage the intersegment hinge until the at least one latching member is engaged to form the substantially rigid body and thereby protectively enclose and deny access to the sharpened tip.
It is another important object to provide an unfoldable safety medical needle apparatus comprising:
a medical needle having a sharpened tip disposed on a distal end;
a removable needle cover which, in cooperation with a hub for the medical needle, is disposed about the medical needle to provide a fluid flow resistant seal for antiseptic purposes, the cover being removed for access to the medical needle for use in a medical procedure;
a safety shield assembly comprising:
a safety sheath which is folded and compacted to permit the removable needle cover to be so disposed about the medical needle and to also permit access to the medical needle and associated distally disposed sharpened tip for use in a medical procedure and unfolded to be displaced about the medical needle to provide a protective safety sheath about at least the distally disposed sharpened tip;
the medical needle hub in which a proximal end of the medical needle is affixed;
structure associated with the medical needle hub comprising connective geometry by which the needle cover is releasibly affixed to the medical needle hub and by which a proximally disposed fluid vessel is connected to the medical needle hub thereby providing fluid access between the vessel and the medical needle;
a sheath connector assembly whereby the safety sheath is firmly affixed to the structure;
the foldable needle sheath hingeably affixed to the sheath connector assembly, the sheath comprising:
a proximally disposed substantially rigid, elongated first sheath member comprising a first end at which the sheath is hingeably affixed to the connector assembly such that the proximal sheath member rotates in-line with the medical needle when the sheath is unfolded and extended and a second end which is distally disposed relative to the first end when the sheath is unfolded;
a substantially rigid, elongated second sheath member comprising a connected end hingeably affixed to the second end such that the second sheath member also rotates in-line with the medical needle when the sheath is unfolded and an end free of connection to any other part, the first sheath member in combination with the second sheath member comprising a length which extends completely along the medical needle such that at least the second sheath member provides a sheath which shields at least the sharpened tip for safety when the sheath is unfolded;
at least one latch associated with the shield by which the sheath is unreleasibly latched to be securely affixed in place relative to the medical needle and associated sharpened tip when the sheath is unfolded about the needle; and
the second end, in combination with the connected end, further forming an interlock by which the second sheath member is forced into alignment with the needle to be securely latched as a safety shield about the medical needle as the sheath is unfolded.